I think (and this is mostly an assumption), that the younger you start switching foods (protein types within a brand and brands too), the easier they take it. My Bruno is around a year old and he has been switched a bunch. It takes about a week to do a switch with no diarrhea or any other problems.
I think it also depends on the individual dog (maybe?) – some may have more issues than others with switching even if it is done very slowly.
But it is definitely good for them. Different proteins – different amino acids; different brands (read recipes) – different composition of vitamins and minerals. Variety is always good! I mean, chicken with steamed veggies is good for you, but is that ALL you’d ever want to eat your WHOLE life, breakfast/lunch/dinner? 🙂
